Artesian well pump: above ground or immersed?

[grower]

Now I am down to 2 bids. One says he can do either galvanized well casing or PVC. The other says he does only galvanized. Which should I choose? I live in Florida and freezing is rarely a concern. But it can go down to 20's in the morning.

I called water management district for advice. According to them, both are commonly used. But PVC is about $700 cheaper than galvanized. $3500 vs. $4200. Just the well casing, and a valve. I will add plumbing and a pump. Thanks.

[Pat]

I don't know what the experts will say but I lean toward the PVC (especially if it is heavy wall enough.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[CJDave]

[img]/forums/images/icons/tongue.gif[/img] Many well drillers use heavy wall PVC with "dime slot" perforations. In bad water, the slots stay open longer on PVC. If the subsurface strata is "hostile" .....lots of big rocks....the metal casing will maintain alignment better. [img]/forums/images/icons/tongue.gif[/img] Nobody has mentioned "upthrust" one of the secret killers of submersible pumps. If you pump directly into an irrigation system, the design flowrate of that system has to maintain enough pumping head to keep the pump from over pumping....that is to say keep it from getting so far off the curve to the right that the impeller downthrust goes into UPTHRUST. Even if the system was perfectly designed, someone could still open enough valves or change things such that the pumping head was reduced to almost nothing. [img]/forums/images/icons/tongue.gif[/img] Isn't this a situation where a surface pump would be appropriate? The cost penalty for using a sub is normally offset by their ability to pump efficiently AT DEPTH. They are actually a poor choice for very shallow settings where upthurst can so easily occur. [img]/forums/images/icons/tongue.gif[/img] How about a nice, single-pipe, self-priming centrifugal? If the water is at or near the surface, it seems like that would be a good choice. [img]/forums/images/icons/tongue.gif[/img]

[1994]

So you already have a pump? The Flo tec pump only builds 46 PSI. Then you are stuck with a 20/40 pressure switch setting. I would not be happy with that low of pressure. I reccommend 40/60 PSI which means a bigger pump. My house runs at 50/70 and I have such good pressure I don't really even need soap. Constant 60 PSI will just blast the dirt off of you in the shower.

[GaryQWA]

Use PVC for the casing and then PE drop pipe to the pump. I'd take the pump back and get a better quality pump like Gould's etc.. All pumps have a pump curve chart (or don't buy one that doesn't), it will show the gpm delivered at what pressure you want to use at what depth you set the pump (in this case 180-190').

You may be choosing a pump based on price instead of performance, which usually in the end costs more. Check some pump supply houses rather than big box stores; they're in your yellow pages under the Pump heading.

All you need to stop thrust wear is a valve that is partially closed to cause some back pressure; never run a submersible pump at open discharge for an extended period of time.

www.cyclestopvalves.com says use a small pressure tank and switch to control the pump. IIRC the CSV works at .5 gpm but there are a number of models and all will have a tank.

Just how much water are you going to be pumping and how frequently are you pumping it?

Gary Slusser
Quality Water Associates

[1994]

Gary, the Cycle Stop Valve will work with a pump start relay and no pressure tank. See this link; http://www.cyclestopvalves.com/techq_3.html

[grower]

I now see my mistake. I will return the pump and buy a good one that goes higher than 46 psi.

Right now, the need is to run sprinkler heads, maybe about 10-15 gpm a few minutes per zone, 4-5 zones, 2-3 cycles a day.

I have a question about the drop pipe. If the casing is full of water (free-flowing well), do I still need a drop pipe with foot valve? Is it necessary because pumping may drop the water level by 10-15 feet?

Where do I buy CSV? From irrigation supply stores?

Thanks.

[1994]

For a CSV, check with pumpsandtanks.com. I am sure they can help with a pump as well.

[speedbump]

Where are you in Florida?

I would recommend PVC if it is 5" not 4". When a pump gets extremely hot for many different reasons, it can become trapped in the casing due to shrinkage. So stick with 5" PVC or 4" Galvanized.

Who is drilling your well?

I can help you with the CSV, pump or most other water well parts if needed.

bob...

[GaryQWA]

I see, and I also see they mention some serious disadvantages, yet using a small pressure tank and switch has NO disadvantages like the start relay set up does; and I'll bet the tank and switch costs less too.

Gary Slusser
Quality Water Associates